// __BEGIN_LICENSE__
//  Copyright (c) 2006-2013, United States Government as represented by the
//  Administrator of the National Aeronautics and Space Administration. All
//  rights reserved.
//
//  The NASA Vision Workbench is licensed under the Apache License,
//  Version 2.0 (the "License"); you may not use this file except in
//  compliance with the License. You may obtain a copy of the License at
//  http://www.apache.org/licenses/LICENSE-2.0
//
//  Unless required by applicable law or agreed to in writing, software
//  distributed under the License is distributed on an "AS IS" BASIS,
//  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
//  See the License for the specific language governing permissions and
//  limitations under the License.
// __END_LICENSE__


uniform sampler2DRect image;

void main() {
   vec2 coord = gl_TexCoord[0].st;
  // coord = coord - vec2(0.5, 0.5);
   vec2 coord_fract = fract(coord);
   coord = floor(coord) + vec2(0.5, 0.5);
   gl_FragColor.rgba =
        texture2DRect(image, coord) * (1.0 - coord_fract.s) * (1.0 - coord_fract.t) +
        texture2DRect(image, coord + vec2(1.0, 0.0)) * coord_fract.s * (1.0 - coord_fract.t) +
        texture2DRect(image, coord + vec2(0.0, 1.0)) * (1.0 - coord_fract.s) * coord_fract.t +
        texture2DRect(image, coord + vec2(1.0, 1.0)) * coord_fract.s * coord_fract.t;
  //gl_FragColor = vec4(gl_TexCoord[0].t);
}
